Feed back from the owner of a stock broad band manifold that was removed and replaced with the AS0012 4 barrel Aussiespeed manifold, 600 Holley and a set of Aussiespeed Tubular extractors:
The cars owner reported back to us a gained around 20% in RWHP. The owner also commented "best thing is no more computer hassles" when it comes to tuning.
Aussiespeed have a performance manifold to suit most Ford 6 cylinder engines available in both 2 barrel and 4 Barrel there is a manifold to suit your performance upgrade.
It is very important when using Aussiespeed 2 or 4 barrel manifolds that you do not port or enlarge the ports. DO NOT port the manifold at the cylinder head end unless you have extensive experience in cylinder head and manifold development. Our high velocity manifold is designed in such away that cylinder balance is a major key in performance. The volume of the manifold can feed an engine making big horse power and the runner is larger than any Ford six performance manifold available. We did the development and the small port opening will not affect high rpm horse power, it boosts torque, increases air speed to give not only better down low grunt but allows for better breathing in high RPM situations. The 4 barrel Aussiespeed AS0016 Ford xflow manifold has been used on naturally aspirated 250 C.I engines that have produce 400 + HP.
Figures from stock 4.0 with Aussiespeed AS0012, E85 4 barrel carb, front mounted intercooler and turbo. Some very impressive numbers with not a lot of dollars out laid 424.3 HP / 316.4 KW. The AS0012 has one x 3/8 npt vacuum take off on the rear of the manifold for brake vacuum and auto transmission fitting.The widest point of the manifold from head face to carb pad is 215mm